Firearm muzzle silencers absorb and reduce the audible frequencies and vibrations occurring from the rapid expansion of gases leaving a firearm muzzle as the projectile leaves the gun bore. Such devices, in addition to reducing audible frequencies, also contain and arrest muzzle flash. Silencers, conventionally, are designed to temporarily contain and divert the expanding gases, and necessarily, effective firearm silencers must be relatively large and bulky to accommodate the large volume of expanding gas, especially with higher caliber firearms.
Firearm silencers or suppressors are known wherein a plurality of baffles or elements are mounted within the silencer body in axially aligned relationship wherein the baffles include conical or expanding volume bores. U.S. Pat. Nos. 1,017,003; 4,291,610 and 4,576,083 disclose this type of construction in a muzzle silencer.
It is also known to employ spiral baffles or vanes in firearm silencers for increasing the gas path of movement length and arresting gas expansion, and U.S. Pat. Nos. 1,341,363; 2,792,760 and 3,500,955 disclose silencers using such spiral vanes.
U.S. Pat. No. 3,667,570 discloses a silencer incorporating both baffles having diverging bores, and spiral vanes located on the exterior surface of baffles. However, in this patent the two different types of suppressor elements are located in series with respect to the axial length of the silencer, and effective silencing with this type of construction requires a silencer of considerable axial dimension.
It is an object of the invention to provide an effective firearm silencer or suppressor of concise configuration wherein audible frequencies, and muzzle flash, are effectively confined in a body of concise axial configuration and the expansion of gases is rapidly dissipated.
Yet another object of the invention is to provide an effective concise firearm muzzle silencer including gas expansion chambers and a plurality of baffles having bores permitting gas expansion and exterior vanes defining an elongated gas flow path to decelerate and cool the expanding gases.
A further object of the invention is to provide a concise firearm muzzle silencer which is of economical construction, may be readily assembled, and is rugged and readily serviceable by the unskilled.
In the practice of the invention an elongated cylindrical body includes a mounting end and a projectile outlet end. The adapter end is mounted upon the firearm, and first and second gas expansion chambers are defined adjacent the adapter. Expanding gas leaving the second chamber communicates with a spiral gas expansion flow chamber defined by a plurality of communicating spiral vanes defined on short baffles stacked in an axial end-to-end relationship.
Internally, each baffle includes a bore of expanding volume in the direction of projectile and gas movement, and externally, each baffle includes a spiral vane communicating with the flow path defined by the spiral vanes of adjacent baffles. The downstream portion of the vanes of each baffle communicate with the upstream vane portions of the adjacent baffle wherein expanding gases leaving the vanes of one baffle enter the vanes of the adjacent baffle in the direction of gas expansion. This "back pressure" causes a compression with respect to gas expansion effectively absorbing and dissipating the expanding gases and audible frequencies.
A final expansion chamber is defined adjacent the silencer outlet cap, and the cap includes a shrouded bore tending to confine and restrict gas flow through the cap, adding to the audible suppression produced by the invention.